The present application generally relates to actuated seats, and more particularly, to a seat actuation control system for aircraft seats and a communication protocol used in such control system.
Modern airplane seats, and in particular, seats in the premium sections of passenger airplane are powered and adjustable between a number of seating positions. Some seats may be adjustable from an upright position to a reclined position, while others can recline to a substantially flat position in order to function as a bed. Additionally, some airplane seats have a head rest and a foot rest that can be adjusted to provide a comfortable seating position. The various adjustable features of the seat are accessible and controllable with a passenger control unit, which may be a keyboard with a display. The passenger control unit may also provide the passenger with the ability to adjust the environmental conditions around the seat, such as lighting, temperature and the like. Furthermore, the passenger control unit can allow the passenger to operate various entertainment devices and features associated with the seat, such as a display screen for viewing movies.
FIG. 1 illustrates a powered seat with a typical seat operating system including a passenger control unit such as a keypad 104, a controller 106 and several actuators or other devices 108A-H. A passenger (not shown) sitting in the seat uses the keypad to adjust the seat position and associated devices. The keypad communicates with the controller which, in turn, controls the actuators. The seat controller drives the actuators which control various aspects of the seat. For example, an actuator 108D moves leg rest 110 that moves from a substantially vertical retracted position to a substantially horizontal, extended position. An actuator 108E moves a foot rest 112, that moves from a substantially extended to a substantially retracted position. An actuator 108A moves the reclining back rest 114 that moves from a substantially vertical position to a substantially horizontal position. An actuator 108C moves the seat pan 116. An actuator 108H moves the privacy screen 118. A lumbar controller 108B drives/controls the lumbar bladder 120. In addition, each actuator may include one or more position determining components such as a transducer or sensor (not shown).
A variety of devices may be associated with a seat. For example, by using the passenger control unit, a passenger may control cabin lighting 108F, video systems 108G, audio systems (not shown) or other devices. For convenience, a device associated with a seat such as an actuator or another device or component mentioned herein may be referred to in the discussion that follows as a “seat device.”
In a conventional seat control system, all processing is performed in a main controller, such as the controller 106 of FIG. 1. The controller thus directly controls the operation of each actuator or other devices. For example, the controller generates control signals for each actuator and other devices and sends these signals to each actuator/device via separate connection leads. In addition, any signals from sensors in the actuators are sent directly back to the controller. A relatively substantial amount of wiring is used to connect the components.
In other conventional seat control systems (not shown), an actuator controller is incorporated into each actuator assembly. A main controller may coordinate the operation and position of all of the actuators. To this end, the main controller sends commands to each actuator controller over a common serial bus to accomplish the desired actuation. Through the use of a common serial bus, the amount of wiring associated with the seat controller may be reduced. Each actuator controller controls the position of an associated actuator based on commands from the main controller. In response to a command for a given actuator, a corresponding actuator controller generates, within the actuator assembly, actuation signals for that actuator. Signals from sensors in an actuator are sent to the associated actuator controller in the actuator assembly. The actuator controller may use these sensor signals to verify the movement or position of the actuator.
The main controller may perform various functions in addition to the motion control functions described above. For example, the main controller may include a user interface (HMI), communication management, power management and test (e.g., built-in test equipment) functionality. The actuator controller may perform various functions relating to the motion control functions described above. For example, the actuator controller may include a motor driver, actuator jam and short circuit control functionality and electronic clutch abuse control functionality. In addition, the actuator controller may include communication and test (e.g., built-in test equipment) functionality.
In both of the above-described systems, because the location of the main controller may be far from some or all the actuators, the amount of wire used to connect the controller to the actuators may be excessive. The entire system fails to function if the main controller malfunctions or becomes inoperative. System response depends on generation of commands from the master controller to the actuators and receipt of feedback from the actuators by the master controller. Accordingly, for systems with a large number of seat devices, system response may be slow.
Based on the above, there is a need for an operating or control system for a vehicle seat that provides improved wiring, speed, efficiency, modularity and upgradeability.